Evaporative cooling systems have been employed in various applications for a number of years. Such systems typically involve a pressurized fluid, usually water, escaping through a small orifice and impinging on a proximate surface. The force of the pressurized stress against the surface causes the fluid to disperse into minute particles creating a localized fog or mist.
Because of the difficulty in precisely cutting the small diameter orifice and delivery channel, such prior art nozzles have typically been formed from brass and other relatively soft metals because of the difficulty in working. Recently, some nozzles have been produced in stainless steel, however such nozzles still follow the design of previous nozzles.
The short delivery channels of the prior art appeared to be necessary because of the limitations of metalworking. Cutting a narrow orifice, typically on the order of six one-thousandths of an inch (0.006 inch), is typically done with a pin drill, usually a stationary drill which engages rotating work. The depth which can be achieved with such a metalworking procedure, typically no greater than fifteen one-thousandths of an inch (0.015 inch), is chiefly a function of how well the drill bit can be supported during the metalworking process.
Further, the nature of the metalworking employed to cut the orifice and delivery channel is such that the integrity of the orifice and channel walls is difficult to maintain. The drilling operation is known to gouge and scar the interior surface of the delivery channel and leave an imprecise mouth to the orifice itself.